Seasons & Episodes
Secrets of the Rock
A hidden, subterranean city built within the Rock of Gibraltar was an immense fortress to control the seas during World
Mystery of the Lost Labyrinth
A strange, centuries-old labyrinth built into an abandoned quarry was built by an eccentric millionaire, and no one know
Secrets of the Terror Tunnels
A vast system of tunnels built almost three thousand years ago was the site of the greatest battles of antiquity, and th
The Renegade's Lair
A strange underground system known as the Black Cave was home to an infamous nobleman on the run from the law; today, ex
Cave of the Body Snatchers
An eerie system of underground vaults in Scotland was once the hideout for thieves who stole newly-buried bodies and sol
World's Biggest Labyrinth
The world's biggest labyrinth is a 1,553-mile cave system that's home to some of history's darkest mysteries, and new di
Treasures of the Lost Mine
Caverns hidden deep inside a remote mountain are home to a precious mineral found nowhere else on earth, and experts and
Ghosts of the Hell Maze
A labyrinth of tunnels in the French countryside has served as a secret hideout during wartime for centuries. On its wal
Conspiracy in the Buried City
A buried ancient city hidden five stories underground, and to keep its location secret from invaders, its residents devi
Curse of Cannibal Caves
A mysterious cave system is home to some of the oldest human remains ever discovered, and today, the explorers and resea
Hotel Bunker of the Apocalypse
The top-secret construction of a massive nuclear bunker remained concealed under a palatial West Virginia hotel for deca
Mystery of the Kentucky Cave
The longest known cave system in the world spans hundreds of miles beneath the hills of Kentucky, and containing prehist
Cincinnati's Secret Caverns
Deep beneath the streets of Cincinnati lies a network of deserted tunnels and caverns that contain a remarkable history
Buried Lab of the Black Hills
Buried nearly a mile beneath the Black Hills of South Dakota is a cutting-edge laboratory at the forefront of astonishin
Ireland's Underground Alcatraz
Subterranean military fortresses situated on the southern coast of Ireland have protected against enemy invasion for ove
Subterranean Silo Survival
Experts investigate a decommissioned underground missile launch facility.
Italy's Subterranean Secret
An unprecedented landslide unveils a hidden world beneath a picturesque town in northern Italy, and now experts investig
Grand Canyon's Lost Treasure
Descending more than 200 feet beneath the Arizona bedrock lies the largest dry cave system in North America; experts exp
Murder Raid Tunnels
Experts explore an extensive network of tunnels beneath Ramsgate, England.
Medieval Maze of Secrets
A forgotten world of ancient underground passages and medieval engineering lies hidden beneath the town of Exeter, Engla
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